The bonnet release catch won't work on my car. Any ideas how I can open the bonnet without using the bonnet release catch?

I'm suspecting that the cable has stretched as I can open the bonnet early in the morning or when it's cold during the day (ye olde expansion/contraction of the cable theory).

I've recently bought a Fusion. I found that you have to pull the catch for the bonnet pretty hard before it releases. At first I thought it might snap, but I gave it a good tug and the bonnet popped open. It sounds like you're only having occasional problems though, so this might not be relevant!